Madhya Pradesh Public Service Commission uses scaling method for calculation of marks in the preliminary exams for individual candidates which ultimately leads to final declaration of merit list. The best thing about this method is that almost all the candidates get equal opportunity irrespective of the subject opted by them. The formula is give below with full description:
Scaled Marks Obtained by the Candidate = M+ (X-m) S/s
Where M = Overall mean of raw (marks which are not scaled) marks of all the optional subjects.
           X= Raw marks obtained by the candidate in specific optional subject
          m = Median of the marks obtained in a specific optional subject.
          S= Standard Deviation of the marks of all the optional subjects.
          s = Standard Deviation of the marks of the specific optional subject.